Inflatable kite



R. A. POHL INFLATABLE KITE June 11, 1963 3 Sheets-Sheet 1 Filed 001- 10. 1961 ATTORNEY June 11, 1963 R. A. POHL 3,093,354

INFLATABLE KITS Filed 001.. lO, 1961 3 Sheets-Sheet 2 INVENTOR. RUSSELL A. POHL I20 ATTORNEY R. A. POHL INFLATABLE KITE June 11, 1963 5 Sheets-Sheet 3 Filed 00%. 1Q. 1961 INVENTOR.

RUSSELL A. POHL ATTORNEY 3,093,354 Patented June 11, 1963 3,093,354 INFLATABLE KITE Russell A. lohl, Sioux Falls, S. Dale, assignor to General Mills, Inc., a corporation of Delaware Filed Oct. 10, 1961, Ser. No. 144,182 11 Claims. (Cl. 244-154) The present invention relates generally to kites and more specifically to inflatable kites formed from flexible gas mpervious sheet material.

Kites in general use are those constructed of a thin sheet of paper having rigidity afforded by the provision of a plurality of stiffening members. Such kites are often cumbersome to assemble and their performance under buffeting wind conditions is not always satisfactory.

The instant invention provides an inflatable kite which, when filled with an amount of air of lifting g-as, maintams the desired shape without the use of rigid stiffening or support members, and when flown, is substantially stable under extreme fluctuations in wind conditions.

According to the present invention I provide a kite having a combination of unique characteristics which provide improved appearance and performance.

To provide stable flight characteristics, it is ordinarily necessary to bow the kite by connecting the side edges together with a string. The tying of this string, of course, requires a certain amount of time and care in order to assure that the kite is not bowed too much or too little. The present invention provides an inflatable kite having improved flight characteristics wherein the use of string to bow the kite is unnecessary.

To provide improved flight characteristics, kites according to the present invention are provided with a plurality of longitudinally extending raised rib portions separated by a plurality of longitudinally extending grooves. These ribs and grooves steady the kite as it is being flown and help orient the kite with respect to the air stream. Another feature of kites according to the present invention is the provision for a plurality of outwardly extending inflatable fins. As well as steadying the kite, these fins aid in determining the attack angle taken by the kite. Still another feature of the present invention is a provision for insuring that the kite will assume a predetermined camber automatically upon inflation to increase the climbing and lifting power which allowstthe kite to achieve greater altitudes. Another feature of this invention is the provision that at least some of the inflated compartments have an aerodynamic or tear drop cross-sectional shape to provide additional lift and have sweepback to increase stability.

It is therefore an object of my invention to provide an improved hollow inflatable kite which will maintain its contour when inflated without the use of rigid stiffening or support members.

Another object of my invention is to provide an improved inflatable kite having dihedral and camber Wihich result in improved aerodynamic stability and increased lifting efficiency.

It is another object of my invention to provide an improved hollow inflatable kite which, when inflated, naturally resists forces tending to remove the camber and dihedral.

A still further object of my invention is the provision of an improved kite formed solely from flexible sheet material having longitudinally extending stabilizing means.

Still another object of my invention is the provision of an improved kite having inflatable stabilizing means extending laterally outward from the body portion of the kite.

A more specific object of my invention is the provision of an improved hollow inflatable kite seamed together to form a plurality of interconnected compartments or chambers which, when inflated, have bearing surfaces in contact with each other adjacent the seams to provide strength and rigidity to the structure.

It is a further object of my invention to provide an improved kite which, when inflated, can be flown in a conventional manner by employing the usual pull string and bridle connections, but which requires no string to form a bow or dihedral.

These and other objects will become apparent in the following specification and the appended drawings in which:

FIGURE 1 is a plan view of one embodiment of the present invention in the uninflated condition;

FIGURE 2 is a front elevational view of the inflated kite of FIGURE 1;

FIGURE 3 is a rear elevational view of the inflated kite of FIGURE 1;

FIGURE 4 is a sectional view taken along line 44 of the kite of FIGURE 3;

FIGURE 5 is a perspective view of the kite of FIG- URE 1 during flight;

FIGURE 6 is a plan view of another embodiment of the present invention in an uninflated condition;

FIGURE 7 is a side elevation of the kite of FIGURE 6 after inflation;

FIGURE 8 is a front elevation of the kite of FIGURE 6 after inflation;

FIGURE 9 is a plan view of another kite according to the present invention before inflation;

FIGURE 10 is a plan view of the kite of FIGURE'9 after inflation;

FIGURE 11 is a front elevation of the inflated kite of FIGURE 9;

FIGURE 12 is a cross-sectional View taken along line 1212 of FIGURE 10*;

FIGURE 13 is a perspective View of the kite of FIG- URE 10' during flight;

FIGURE 14 is a plan view of another embodiment of the present invention before inflation;

FIGURE 15 is a plan view of the kite of FIGURE 14 after inflation;

FIGURE 16 is a plan view of another embodiment of the present invention before inflation; and

FIGURE 17 is a plan view of another embodiment of the present invention before inflation.

Before describing the details of my invention, a preliminary explanation of its principles will be presented.

The kites according to the present invention are formed from two similar sheets of plastic material or other gas impervious material seamed or sealed together to provide a compartmented stress beam construction. When the kites are inflated, some of the inflated beams bear against other beams setting up a complex of forces. The beams are positioned in such a manner that a stress condition exists between the beam bearing areas causing deformation of the entire structure. The resultant deformation is effected when the kite is inflated and imparts dihedral and camber to the airfoil structure. The automatic formation of dihedral upon inflation provides a kite with improved aerodynamic stability while the camber provides increased lifting efficiency. Thus, the dihedral and camber give the kite a shape which provides adequate air spill-out and less slippage under varying wind conditions. The particular arrangement of the stress beams will be explained in the following description taken in conjunction With the drawings.

Refer now to the specific embodiments of my invention shown in the drawings. The peripheral shape of the kite can vary substantially. For example, the kite shown in FIGS. 1-5, is shaped somewhat like a flying wing and that in FIGURES 9-15 resembles a jet aircraft.

In FIGURE 1, there is shown a flying wing type kite 2, so-called because the lateral axis 4 is longer than the longitudinal axis 6. The kite 2 is formed from two normally flat sheets of thin plastic material 8 and 10 seamed or sealed together by any conventional method to form an inflatable body by continuous seam 12 extending around the outer edge of the sheets. Numeral designates a nose portion and numeral 7 designates a tail portion of the kite. Additional seams 13, 14 and 16 positioned within the outer seam 12 divide the kite into intercon nected inflatable stress beams or compartments 18, 20, 22, and 24. Seam 13 extends laterally across the upper or leading edge portion of the kite 2, its ends being spaced from the outer seam 12. The portions of scam 13 on either side of the longitudinal axis of the kite are angled backward slightly from the lateral axis. Each of seams 14 and 16 begins at seam 13 and is spaced from seam 12 at the other end. Seams 14 and 16 are angled slightly with respect to the longitudinal axis of the kite. The separation between seams 14 and 16 is greater where the seams 14 and 16 intersect seam 13 and least at their termination near the tail portion 7.

If the kite is formed from thermoplastic resinous sheet material, the previously-mentioned seams are preferably formed by heat sealing equipment. Should other materials be employed, appropriate sealing methods would be used accordingly.

The kite is also provided with an inflation tube 26 having an opening 28 for admitting gas for inflation. When the kite 2 is inflated, the inflation tube 26 is closed by string or the attachment of a bridle string or tail.

On the outer edges of sheets 8 and integral therewith are tabs 30, 32, and 34. These tabs provide means for attaching a bridle to the kite 2 when it is flown.

When the kite 2 is inflated as disclosed in FIGURES 2-5, the inflation gas fills stress beam compartments 18, 20, 22, and 24. The stress beams then bear against each other creating a stress condition between the beam bearing areas. The resultant forces between the stress beams form a dihedral angle and camber in the kite which provide aerodynamic stability and increased lifting efliciency.

The inflated configuration of the kite is produced by stress beam compartments and 24 exerting a force on the beam compartment 18. The forces developed in the kite material when the kite is inflated force compartments 18, 20, 22, and 24 to assume the configuration disclosed in FIGURES l-S and to bow the kite to produce the rigidity and camber necessary for eflicient aerodynamic design. Seams 13, 14, and 15 are relatively narrow so that when the kite is inflated, a ribbed structure is formed. The seams 14 and 16 form grooves between compartments 20, 22, and 24 which comprise ribs. The alternate longitudinally extending ribs formed by compartments 20, 22, and 24 help orient the kite with respect to the airstream and hence aid in improving the stability of the kite. Moreover, the side seams of each of com partments 20, 22, and 24, see FIGURES 2, 3, and 4, are closer together near the tail portion 6 of the kite so that compartments 20, 22, and 24 assume an aerodynamic or tear drop cross-sectional shape, i.e., the compartments are rounded near the nose portion 5 and taper to the tail portion 7. This provision helps add lift and reduces drag.

The kite 2 shown in FIGURE 5 has a bridle formed by strings 42, 44, 45, and 46 secured to integral tabs 30, 34, and 32 and to the inflation tube 26, respectively. The opposite ends of the strings are tied to pull cord 48 somewhat ahead of the front face 36 of the kite 2. Strings 42, 44, 45, and 46 are of such length that the kite, when in flight, is supported equally by the individual strings. When the kite 2 is in flight, a stabilizing tail 50 is secured to the inflation tube 26, the length of which is dependent upon the wind conditions at the time of flight.

The strings forming the bridle do not distort the kite material to produce the dihedral and camber since the forces set up in the kite material by the cooperation of seams and inflated compartments accomplish this result. However, the lengths of the strings of the bridle may be varied to control the magnitude of the dihedral and camber. The compartments 18, 20, 22, and 24 are situated in such a manner, see FIGURE 3, that the inflated compartments resist forces which would tend to remove the camber and dihedral. The inflated walls of the various chambers engage the adjacent compartment.

Numerous kite patterns are feasible according to the present invention, as for example the kite 58 of FIG- URES 6, 7, and 8 which has the general outline of the common two stick kite. The kite 58 is formed from two sheets of plastic material 54 and 56 sealed together by a continuous seam 52 around the outer edges of the sheets. Transverse seam 60 and longitudinal seams 62 and 64 divide the kite 58 into inflatable stress beam compartments 66, 67, 68, and which are substantially the same as those of the previous embodiment. An infia' tion tube 72 and tabs 74, 76, and 78 are used for securing a bridle to the kite 52. Upon inflation, the kite 58 assumes an airfoil similar to the general configuration described in the previous embodiment, see FIGS. 15, except for the variation in dimensions.

It is noted that the longitudinal axis of kite 58 is longer than the transverse axis. The camber and dihedral are clearly shown in FIGURES 7 and 8. The aerodynamic or tear drop cross-sectional shape of the stress beams is illustrated in FIGURE 7.

Referring now to FIGURES 9, 10, l1, l2, and 13, kite 84 is formed from two sheets of plastic material 86 and 8S. Kite 84 include a nose portion and a tail portion 82. The sheets 86 and 88 of plastic material are joined along the outer edges by a continuous seam 90. Lateral seams 92 and 94 secure the sheets together and divide the kite 84 into forward compartments 96 and 98. The seam 92 is divided into two parts, each extending outwardly from longitudinal axis and toward the tail 82, preferably along lines generally oriented as extensions of the leading edges of the kite. In the center of seam 92 is an unsealed area which allows inflation air to pass into chamber 96. Seam 94 is also angled toward the tail 82 on either side of the longitudinal axis 105. Seam 94 is generally parallel to the leading edge portion of the kite. Longitudinally extending seams 100 and 102 intersect seams 94 on either side of axis 105. Seams 100, 102 are angled with respect to longitudinal axis 155 so that the ends thereof near the tail of the kite are closer together than the ends of the seams near the nose.

Compartment 98 ahead of seams 94 thus extends along the leading edge of the kite 84, its ends terminating somewhat beyond the outside marginal edges of adjacent compartments 104 and 108, and has the general appearance of a swept wing. Longitudinal side compartments 104 and 108 are provided with integral tail fins 110 and 112 which sweep rearward with the ends terminating somewhat beyond the side edges of the kite. Kite 84 is inflated through an inflation tube in central longitudinal compartment 106. Inflation gas passes through openings in the seams between the several compartments to inflate the entire kite as in previous embodiments.

Upon inflation, the kite 84 is deformed into an eflicient airfoil having a dihedral angle and camber as illustrated in FIGURES ll, 12, and 13. During inflation the compartments (also referred to as stress beams) tend to exert forces in opposing directions and achieve a state of equilibrium only after assuming a saddle-like shape.

Because the stress beams 104 and 108 have a larger volume upon inflation, beam 98 is deflected rearward and upward out of a flat plane. The beam 98 thus has a greater sweepback angle when inflated as seen in FIG- URE 10 than is present in the non-inflated condition illustrated in FIGURE 9. Beam 98 tilts forward along the seam 94 when inflated, as shown in FIGURE 12, until a shouldered or beam bearing relationship exists between beams 98, 104, 1136, and 108 adjacent the seam 94- on the forward face of the kite. Likewise a shouldered or beam bearing relationship exists adjacent the scams 1% and 102 between compartments 104, 106, and 1118 on the rear surface of the kite. The upward deflection of beams 104 and 106 carries with it empennage fins 110 and 112 so that the dihedral angle is formed to empennage fins 110 and 112 as disclosed in FIGURES ll, 12, and 13. Thus, after inflation the kite 84 assumes a deformation wherein the structure is again in equilibrium by virtue of the bearing surfaces so that both the dihedral and camber are present. The nose compartment '96 illustrated in FIGURES -11 and 12 is tilted even further forward than beam 98 when the kite 84 is inflated. Thus, even greater camber is afforded than in the previous embodiments. A bridle 113 is attached to tabs 114, 116, 118, and the inflation tube 126.

In addition to the increased stability afforded by the camber and the dihedral, the sweepback of stress beam 98 and tail fins 110 and 112 as well as the alternate longitudinally extending ribs and grooves formed by compartments 104, 106, and 108 coacting with seams 116* and 102 provide further stability. The aerodynamic or tear drop cross-sectional shape of compartments 104, 106 and 108 disclosed in FIGURE 12 help provide additional lift with reduced drag and result in greater climbing power.

Referring now to FIGURES 14 and 15, there is shown a kite 154 of another embodiment of the invention comprising two similar sheets 150 and 152 of normally flat, flexible, gas impervious material cut generally in the shape of an arrowhead. The sheets 150 and 152 are sealed along matching edges by a peripheral seal 156. The kite 154 includes a nose portion 158 and a tail portion 160 which is left unsealed to provide an inflation opening 162. Nose portion 158 is difierent from other embodiments, since a separate seam is not used to form the nose portion. Extending laterally from the nose portion 158 is a first stress beam or an inflation compartment 164 which has the general shape of a swept back wing. Compartment 164 is bounded on the front edge by se'al 156 and in the back by seal lines 166 and 168 which are disposed generally parallel to the front edges of compartment 164. Seals 166 and 168 1do not join at the longitudinal axis in order to provide an opening for inflation of compartment 164. That portion of kite 154 behind compartment 164 is divided into three inflatable longitudinal compartments 174, 176, and 178 by two longitudinal seal lines designated 170 and 172 which are forward extensions of the side edges of the tapered tail portion 160. The forward ends of seal lines 170 and 172 terminate at seal lines 166 and 168, respectively. Central chamber 178 is thus separated from lateral chambers 174 and 1 76 by seal lines 170 and 172, but communicates with chambers 174 and 176 by means of openings between the chambers, such as openings 173 and 180 which may be forme by spacing the ends of seals 170 and 172 from the peripheral seal 156. Tabs 182, 184-, and 186, as well as the inflation tube 162, are used to connect bridle strings to the kite.

Note that seals 170 and 172 are angled with respect to the longitudinal axes of the kite. The ends nearest the tail portion are positioned closer together than the forward ends. This configuration assures that the central chamber 178 will assume an aerodynamic or tear drop cross-sectional shape to help reduce drag and increase lift. The stress beam 164- has a considerable amount of sweepback which aids in steadying the kite while the kite is in flight. Compartments 174, 176, and 178 comprise alternate ribs separated by longitudinally extending grooves aligned with seal lines 170 and 172, thus adding further stability to the kite. As described in connection with the preceding embodiments, the kite 154 takes on 6 both camber and a dihedral automatically upon inflation.

Referring now to FIGURE 16, there is disclosed an other embodiment of the present invention comprising a kite formed from two sheets 192 and 194 of flexible normally flat gas impervious material which are cut to a rectangular shape similar to that of a conventional two stick kite, except that there is provided a pair of tail extensions 196 and 198 on either side of inflation tube 200. The peripheral edges of sheets 192 and 194 are joined by seal 202 while the central portion of the kite is divided into a plurality of separate inflation compartments by a laterally extending seal 204 perpendicular to the longitudinal axes of the kite and by two longitudinally extending seals 206 and 208 which are parallel to the longitudinal axis of the kite and are equally spacedfrom the longitudinal axis on either side thereof. Openings, such as openings 210, 212, 214, and 216, are provided between the several compartments to allow communication for inflation between the compartments. The seal lines 206, 204, and 20 8 thus divide the kite into a generally triangular forward compartment 220, laterally spaced longitudinal body compartments 222 and 224' and central longitudinal body compartment 226. Upon inflation, camber and a dihedral are formed as described in connection with the preceding embodiments. Chambers 220, 222, and 224 are aerodynamically shaped to provide additional lift. The chambens 222, 224, and 226 comprise longitudinally extending ribs separated by grooves overlying seals 2116 and 20 8. These longitudinally extending ribs and grooves stabilize the kite as described above in connection with previous embodiments.

FIGURE 17 shows another embodiment 250 of the invention generally similar in construction to the embodiment shown in FIGURES 9-13 with the following exceptions. The leading edge 252 of the transverse stress beam 254 extends at right angles to the longitudinal axis 256 of the kite. The side edges 262 and 264 of beam 254 are co-extensive with the side edges of lateral chambers 266 and 268 respectively :and finally the tail fins 258 and 261 are made larger than those of the embodiment shown in FIGURES 9-13 so that the kite more nearly resembles a five pointed star. The fabrication, inflation, and flying techniques are in all respects similar to the embodiment shownin FIGURES 9-13.

Certain theories of operation have been advanced, but regardless of their accuracy, the fact remains that if kites are constructed according to the structural features set forth herein, the result is a kite of efficient design. It is to be understood also that the above-described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed:

1. An inflatable kite formed from sheets of gas impervious material joined by an outer seam at the periphery of said sheets to form a gas containing chamber, said kite having a series of longitudinal central seams joining said sheets at predetermined points within said outer seam to divide said chamber into adjoining stress beams, said kite having a lateral seam joining said sheet at a predetermined point within said outer seam to terminate said longitudinal seams, said outer seam having means for introducing gas into said chambers to inflate said beams, said inflated beams exerting forces on adjoining beams to permanently distort said kite to form an airfoil having camber and dihedral.

2. A hollow inflatable kite formed from two similar sheets of plastic material, comprising a first seam sealing together said sheets along outer matching edges, said kite having a central longitudinal axis and a leading edge at one end, a second seam sealing said sheets along a line generally parallel to said leading edge of said kite and terminating short of the first seam, third and fourth seams intersecting said second seam intermediate the ends of said second seam, each of said third and fourth seams being spaced apart from said longitudinal central axis of said kite and an inflation tube operatively associated with said kite for admitting an inflating gas, whereby upon inflation, said kite assumes an aerodynamic shape having camber and dihedral.

3. A hollow inflatable kite formed from two sheets of plastic material secured together along outer matching edges, said kite having a leading edge and a tail portion, a lateral seam extending generally parallel to said leading edge and terminating short of the outer edges of said kite to define a transversely extending stress beam compartment between said leading edge and said lateral seam, at least two longitudinally extending seams positioned between said leading edge and said tail portion, said longitudinally extending seams defining lateral and central longitudinally extending inflatable stress beam compartments, and an inflation tube operatively associated with said sheets for admitting an inflating gas to said kite whereby a semi-rigid airfoil is produced having camber and dihedral.

4. The kite of claim 3 including an inflatable empennage integral with said lateral longitudinally extending inflatable compartments, said empennage having a pair of laterally extending tail fins respectively integral with said lateral compartments.

5. An inflatable kite formed from similar sections of normally flat plastic sheet material and provided with an inflating tube, said kite having a nose portion and a tail portion, swept-back leading edges on either side of said nose portion, a first seam securing the sheets together along outer matching edges, a second seam spaced apart from and extending generally along said swept-back leading edges of said kite, said second seam having openings therein to provide air passages communicating between chambers on either side of said second seam, third and fourth longitudinally extending seams positioned between said second seam and said tail portion, said third and fourth seams being angled with respect to the central axis of said kite, said seams dividing the kite into four inflatable stress beam compartments whereby upon inflation said stress beams exert forces causing the kite to automatically take on camber and dihedral.

6. An inflatable kite formed from similar sections of normally flat gas impervious sheet material comprising means for inflating said kite, a nose portion at one end of said kite, a tail portion at the opposite end of said kite, a first seam securing said sheets together along outer matching edges, swept-back inflatable compartment bounded on one edge thereof by said swept-back side edges, the tips of said swept-back inflatable compartment extending beyond the side edges of said kite, a plurality of longitudinally extending compartments disposed between said first inflatable compartment and said tail portion, seams extending between each such inflatable compartment to secure said sheets together, said inflatable compartments comprising stress beams adapted upon inflation to exert forces causing the kite to automatically take on camber and dihedral.

7. An inflatable kite formed from similar sheets of normally fiat gas impervious sheet material, said kite having an inflation tube operatively associated therewith, a first seam securing said sheets together along outer matching edges, said kite having a pointed nose portion and a tail portion, the longitudinal axis of said kite extending from said nose portion to said tail portion, at least one generally laterally extending inflatable stress beam con1- partment, a plurality of longitudinally extending stress beam compartments terminating at said laterally extending inflatable stress beam compartment, said longitudinally extending stress beam compartments comprising a plurality of ribs separated by longitudinally extending grooves and a plurality of longitudinally extending seams coextensive with said grooves defining the edges of said compartments, said longitudinally extending ribs and grooves being adapted to increase the stability of said kite during flight.

8. An inflatable kite according to claim 7 wherein the leading edge of said laterally extending inflatable stress beam compartment extends at right angles to said longitudinal axis and wherein two laterally extending tail fins are provided to give said kite the appearance of a five pointed star.

9. An inflatable kite formed from similar sections of normally flat gas impervious sheet material, said kite having an inflation tube, said kite having a nose and a tail, a first seam securing said sheets together along outer matching edges of said material, a plurality of spaced seams securing said sheets to divide said sheets into a plurality of inflatable compartments, a transversely extending compartment adjacent said nose and extending from one side of said kite to the other, the leading edges of said transversely extending compartment being angled backward from the lateral axis of said kite to provide sweep-back for said transversely extending compartment, a plurality of inflatable compartments disposed between said transversely extending compartment and said tail, the tips of said transversely extending compartment extending beyond the outside marginal edges of said plurality of inflatable compartments, the sweep-back of said transversely extending compartment being adapted to increase the stability of said kite during flight.

10. The kite of claim 6 including an inflatable empennage integral with said longitudinally extending inflatable compartments comprising a pair of laterally extending tail fins integral with said longitudinally extending inflatable compartments.

11. An inflatable kite formed of similar sections of normally flat, gas impervious sheet material; said kite having an inflation tube operatively associated therewith; said kite having a nose portion and a tail portion; a first seam securing said sheets along outer matching edges; a plurality of spaced, longitudinally extending seams disposed inwardly of said outer edges securing said sheets and dividing said kite into a plurality of longitudinally extending, inflatable compartments; the edges of said compartments being defined by said seams, the forward ends of said longitudinally extending seams being spaced farther apart than the ends of said seams nearest said tail portion, said longitudinally extending compartments being wider at the ends thereof nearest said nose portion of said kite than at the ends nearest said tail portion whereby said longitudinally extending compartments assume an aerodynamic cross-sectional shape upon inflation to aid in increasing the lift and reducing the drag of said kite.

References Cited in the file of this patent UNITED STATES PATENTS 1,641,607 Spatz Sept. 6, 1927 1,690,978 Jatunn Nov. 6, 1928 2,476,678 Miller July 19, 1949 2,486,158 Haas Oct. 25, 1949 3,003,722 Pohl Oct. 10, 1961 FOREIGN PATENTS 1,085,385 France July 28, 1954 

1. AN INFLATABLE KITE FORMED FROM SHEETS OF GAS IMPERVIOUS MATERIAL JOINED BY AN OUTER SEAM AT THE PERIPHERY OF SAID SHEETS TO FORM A GAS CONTAINING CHAMBER, SAID KITE HAVING A SERIES OF LONGITUDINAL CENTRAL SEAMS JOINING SAID SHEETS AT PREDETERMINED POINTS WITHIN SAID OUTER SEAM TO DIVIDE SAID CHAMBER INTO ADJOINING STRESS BEAMS, SAID KITE HAVING A LATERAL SEAM JOINING SAID SHEET AT A PREDETERMINED POINT WITHIN SAID OUTER SEAM TO TERMINATE SAID LONGITUDINAL SEAMS, SAID OUTER SEAM HAVING MEANS FOR INTRODUCING GAS INTO SAID CHAMBERS TO INFLATE SAID BEAMS, SAID INFLATED BEAMS EXERTING FORCES ON ADJOINING BEAMS TO PERMANENTLY DISTORT SAID KITE TO FORM AN AIRFOIL HAVING CAMBER AND DIHEDRAL. 